Crankshaft & Cylinder Block

Applies to all engine variants (SOHC and DOHC) — the manual heads this section “Crankshaft & Cylinder Block: All.” Flywheel/drive-plate hardware differs by transmission (manual = flywheel, automatic = drive plate); our truck (3-speed automatic 3A/T) uses the drive plate, not the flywheel.

Component removal order

1. Flywheel bolts (5M/T)
2. Flywheel (5M/T)
3. Drive plate bolt (3A/T — our truck)
4. Outer plate (3A/T)
5. Drive plate (3A/T — our truck)
6. Rear plate
7. Bell housing cover
8. Oil seal case
9. Oil seal
10. Bearing cap bolt
11. Bearing cap
12. Lower crankshaft bearing
13. Crankshaft
14. Thrust bearing
15. Upper crankshaft bearing
16. Cylinder block

Main bearing cap torque — SOHC vs DOHC

Note (as printed): “DOHC & SOHC Bearing Caps Same Torque: T=52 (5.3kgm)”

Torque: 52±2 N·m (5.3 kgf·m; 38±1.5 ft-lb) — same for both SOHC and DOHC. This is confirmed by a clean maintenance-note restatement later in this section (“Torque: 52±2 Nm”); used with confidence.

Flywheel / drive plate bolt torques (as scanned)

Value as scanned
T=10 (1.0; 89 in-lb)
T=74 (7.5; 55 ft-lb) — appears twice
T=11 (1.1; 97 in-lb)
T=10 (1.1) — internally inconsistent (10 N·m ≠ 1.1 kgf·m); likely OCR duplication/garble of one of the above

(verify printed p.108-109) — which of these values applies to flywheel bolts vs. drive plate bolts vs. bell housing cover screws could not be mapped from the OCR. Given our truck runs the 3A/T drive plate, confirm the drive plate bolt torque specifically before reassembly — do not assume it’s the largest (74/7.5) figure without checking the printed diagram; on many similar engines the higher torque is the flywheel/drive-plate-to-crankshaft bolt, but this manual’s own diagram text is too garbled to confirm which balloon-numbered fastener that applies to.

Note: Apply thread lock sealant to all flywheel or flexplate attachment bolts. Part number: #1342 (ThreeBond).

Use tool MD999571 as an alignment guide for drive plate & flywheel installation. Use flywheel locking adapter MD998781 to hold the flywheel in place when setting torque.

Bearing size marks

Note: Factory size bearing markings are stamped on the crankshaft, as shown in the diagram.

(verify printed p.110) — same issue as the connecting rod bearing table in 40-pistons-connecting-rods.md: color-code-to-diameter mapping did not survive OCR with confidence. Do not select a main bearing from color alone without checking a clean scan or the Parts Manual.

Crankshaft installation & inspection

1. Coat crankshaft heavily with 30W SAE oil or assembly lube.
2. Install crankshaft.
3. Verify bearing caps are in proper order.
4. Snug bearing caps — do not torque yet.
5. Free-spin crankshaft a minimum of 10 rotations, inspecting for binding. If no issues are found, torque to specification.

Torque: 52±2 N·m (38±1.5 ft-lb) (matches the note on printed p.108 above — confirmed).

Side clearance limit: 0.05-0.25mm (0.002–0.010in)

Oil seal / oil seal case installation

1. Clean surfaces.
2. Coat oil seal with 30W SAE oil.
3. Use tool MD998376 to install the oil seal.

Oil seal case: install new seal before applying sealant; place a 3mm (0.118in) bead of sealant; wait a minimum of 3 minutes before installation to let sealant tack.

Crankshaft oil clearance inspection

Use Plastigage to check clearance.

Allowance: 0.02-0.03mm (0.001in) — matches the Engine Specifications table’s Crankshaft Journal Oil Clearance figure; confirmed. (This inspection is on printed p.112, alongside the drive plate & flywheel installation notes above.)

Cylinder block distortion (warpage)

1. Thoroughly clean deck before inspecting.
2. Use a straight edge and thickness gauge, complete a 5-point cross inspection.

Item	Value
Distortion limit	0.05mm (0.002in)
Resurface limit	0.2mm (0.008in)

Cylinder bore inspection & boring

1. Clean cylinder bores (oil-free).
2. Use a dial gauge, measure bore in 12mm segments.

Item	Value
Bore size (STD)	60.0mm (2.362in)
Distortion limit	0.1mm (0.004in) (verify printed p.113)

(verify printed p.113) — this maintenance-note figure (“Distortion Limit: .1mm”) conflicts with the Engine Specifications table’s “Cylinder Distortion Limit: Below 0.01mm” (see 34-engine-specifications.md) — a full order-of-magnitude difference. Confirm against a clean scan before using either figure.

Cylinder boring calculation — SOHC vs DOHC (turbo)

Configuration	Bore calculation
Non-turbo (SOHC)	Piston OD + 0.02-0.04mm (0.001–0.002in)
Turbo (DOHC — our truck)	Piston OD + 0.03-0.05mm (0.001–0.002in)

Piston-to-cylinder allowance limits — SOHC vs DOHC (turbo)

Configuration	Clearance
Non-turbo (SOHC)	0.02-0.04mm (0.001–0.002in)
Turbo (DOHC — our truck)	0.03-0.05mm (0.001–0.002in)

These match the Engine Specifications table exactly (see 34-engine-specifications.md) and are used with confidence. Our 4A30 DOHC turbo uses 0.03-0.05mm, not the SOHC figure.